On December 15, 1978, the United States and China announced the establishment of diplomatic ties following decades of hostility. Thirty years later, two key participants look back at the events that transformed the US-China relationship.

In the late 1960's, China was in the throes of an anti-capitalist Cultural Revolution, led by Communist Party founder Mao Zedong.

In the United States, Richard Nixon ran for president as a strident, anti-communist.

After China's communist revolution of 1949, the two nations had no diplomatic contact.

But when Mr. Nixon became president, he began to explore changes in U.S. policy.

Brent Scowcroft was an aide to Mr. Nixon at the time. "Nixon came into office with very anti-communist credentials," Scowcroft said. "He was known as an anti-communist, and therefore he could reach out to a communist country like China without people suspecting that he was selling the United States down the river."

Scowcroft says the United States was pursuing detente with the Soviet Union. Mr. Nixon saw the U.S. estrangement from China as dangerously unbalanced.

For years, the U.S. had relations only with the non-communist rulers on the island of Taiwan.

Mr. Nixon sent National Security Advisor Henry Kissinger on a secret mission to end decades of hostility with China.

"What President Nixon was afraid of is if what he was doing became known widely, he would be prevented from going forward with it," Scowcroft stated.

President Nixon arrived in China in February 1972.

At the Great Wall, he spoke of barriers coming down. "We do not want walls of any kind between peoples, and I think one of the results of our trip, we hope, may be that the walls that are erected," Mr. Nixon said. "Whether they are physical walls like this, or whether they are other walls, ideology or philosophy, will not divide peoples in the world."

Still, relations stalled over the status of Taiwan. Zbigniew Brzezinski was President Jimmy Carter's national security advisor.

In a recent speech at a Washington research center (The Brookings Institution), he said the U.S.-Soviet relationship deteriorated in the mid-1970s over arms negotiations.

Brzezinski says he realized then that normalized ties with China could give the U.S. greater leverage with the Soviets. "That led me to start campaigning with the president on behalf of a somewhat different approach, one which would emphasize the strategic connection," Brzezinski said.

Brzezinski traveled to China in May, 1978 and proposed normalizing relations without resolving the issue of Taiwan.

Chinese leader Deng Xiaoping invited Brzezinski to dinner. "He wistfully said to me, you know I only have three years left - it wasn't clear to me if he was speaking of his age or of his tenure in office - and it may not be possible for me ever to visit America," Brzezinski recalled. "I got a sense from that that there was a sense of urgency on his side as well."

Seven months later, the United States and China established formal diplomatic ties. President Carter received Mr. Deng at the White House.

Since then, despite political and economic tensions, the U.S.-China relationship has expanded. And, experts say, the two countries are increasingly interdependent.